public class StreamLogger {
  private final OutputStream out;
 
  /**
   * To create a StreamLogger object.
   * @param out the OutputStream object that the log message should go to.
   */
  public StreamLogger(OutputStream out) {
    this.out = out;
  }
 
  /**
   * To get the OutputStream that the log messages should go to.
   */
  public OutputStream getStream() {
    return out;
  }
  private static Logger getBaseLogger(PrintWriter writer){
    final Logger nop = new NopLogger();
    final Logger base = Loggers.logger(writer);
    final Logger neptune_logger = new NeptuneExceptionLogger(writer, nop);
    final Logger jaskell_logger = new JaskellExceptionLogger(writer, nop);
    return Loggers.sequence(
        new Logger[]{neptune_logger, jaskell_logger, base}
    );
  }
  private static Logger getEchoLogger(PrintWriter writer){
    return new ErrorMessageLogger(writer);
  }
  private static Logger getErrorLogger(PrintWriter writer){
    final Logger err_logger = new ErrorMessageLogger(writer);
    final Logger jaskell_logger = new JaskellExceptionLogger(writer, err_logger);
    final Logger neptune_logger = new NeptuneExceptionLogger(writer, jaskell_logger);
    return neptune_logger;
  }
  /**
   * Get the Logger instance.
   * @param min_level the minimal critical level for a log message to show up in the log.
   * @return the Logger instance.
   */
  public Logger getDefaultLogger(int min_level){
    final PrintWriter writer = new PrintWriter(out, true);
    final PrintWriter err = new PrintWriter(System.err, true);
    final PrintWriter warn = new PrintWriter(System.out, true);
    final Logger all = Loggers.sequence(new Logger[]{
        Loggers.ignore(getErrorLogger(err), Logger.ERROR),
        Loggers.filter(getEchoLogger(warn), Logger.WARNING),
        getBaseLogger(writer)
      }
    );
    return Loggers.ignore(all, min_level);
  }
}

  all_logger = ignore messages below ERROR for getErrorLogger(err);
          filter messages except WARNING for getEchoLogger(warn);
          baseBaseLogger(writer);
  ignore messages below lvl for all_logger;